268 
Allen’s naturalist's library. 
parts to which form an individual belongs. In the average 
female m full breeding dress the upper-parts may be described 
as black, each feather being rather widely margined barred 
and marked with orange-buff (pi. iii. fig. i). The protection 
afforded by this plumage is so perfect that, when the bird is 
sitting on its nest among heather and dead gras.s, it may easily 
remam_ unobserved, though only a few yards distant. 
“This plumage, however, varies much in different individuals 
birds from the west of Scotland, Yorkshire, and Ireland having 
the orange-brown bars much brighter and wider than in the 
more finely mottled and darker specimens generally charac- 
teristic of the east of Scotland. 
“ B. Feathers oj the Sides and Flanks. 
“ Ty the first week in May the summer plumage of the female 
Grouse is fairly complete, and many of the finely mottled 
rufous and black autumn flank-feathers are replaced by widely 
and often irregularly, barred buff and black feathers, similar to 
those of the chest. It must be particularly noted that in none 
of the many females e.xamined, in breeding plumage, were 
the whole of the autumn flank-feathers cast or changed in the 
summer moult, a large proportion being retained, unchan'^ed 
in colour, till the next (autumn) moult. The summer flank- 
feathers are produced in two ways, either by a gradual re- 
arrangement and change in the pigment of the autumn feathers 
(pi. iiL figs. 6-8) or by moult (pi. iii. fig. 9). in some birds 
the whole of the alteration in the plumage of the flanks is pro- 
duced by change of pattern in the old autumn feathers' in 
others the change is entirely produced by moult, while some- 
times both methods are employed by the same individual. 
In the former case, the first indication of the coming chan<je 
may be observed in the beginning of November, or even 
earlier, when many of the flank-feathers show traces of an 
irregular buff stripe or spot near the terminal half of the 
shaft (fig. 7). As the birds only change about half their flank- 
feathers, these buff marks are only to be observed on such as 
are destined to undergo alteration of pattern, which, roughly 
speaking, means every second or third featlier. The buff spot 
gradually enlarges and spreads along the shaft, then becomes 
constricted at intervals, and breaks up into patches, which 
